1. Field of the Invention
This invention relates to a device for use in testing integrated circuits and is in the form of a movable arm having a series of links with integral adjustable mechanisms for "weightless" positioning of a test head.
2. Prior Art
Other test head manipulators exist in the form of movable arms, usually with some type of weight to counterbalance the weight of the test head, but have one or more of the following disadvantages:
(1) Limited range of motion in the horizontal plane; PA1 (2) No provision for cable handling; PA1 (3) Large floorspace "footprint"; and PA1 (4) Potential safety hazard when the test head is removed with the counterbalance mechanism active. PA1 (1) No provision for cable handling; PA1 (2) Potential safety hazard when the head is removed with the counterbalance mechanism active; and PA1 (3) Insufficient load capability. PA1 (1) Links are of sufficient length and their arrangement is configured to allow the head to be brought to device handlers, etc., without the preliminary step of relocating a manipulator frame into a rough position. PA1 (2) Cable troughs are provided to protect and locate the cable bundle between the test station and the head. Motion of the arm is designed to provide gentle bending of the cable bundle. PA1 (3) The arm uses the structure and mass of the test station for its mounting, and hence requires no floorspace for a support frame. PA1 (4) Counterbalancing is by means of a gas spring, which is inherently self-damping. The spring energy cannot be released suddenly and hazardously as with metal springs or weight counterbalances. PA1 (5) The strength and stiffness of the arm is designed to safely support and counterbalance a total load of 100 pounds.
Other manipulators for use in dental and general purpose applications exist, but they have the following problems: